1. Field of the Invention
The present invention relates to novel aromatic polyamidoimides comprising alkenyloxy end groups, to a process for the preparation of such functional polyamidoimides, and to the use thereof, particularly for the production of crosslinked polymers.
2. Description of the Prior Art
Japanese Application JA-A-61/293,966 describes polyamidoimides containing end groups of the alkenyloxy type, which are prepared by carrying out the following steps, in series: a condensation reaction in solution between, in particular, the chloride of a monoanhydride of a tricarboxylic acid, a hydroxylated aromatic primary amine and, if desired, an aromatic diprimary diamine; then an etherification, using an allyl halide, of the hydroxyl end groups of the oligomers formed as the result of the condensation reaction. However, a process of this type presents a number of disadvantages. One of these disadvantages, which is common to most processes where an amino reactant is reacted with an organic carbonyl compound, such as a carboxylic acid anhydride, is in the need to carry out a cyclizing dehydration of the (poly)amides-acids formed as intermediates; in fact, since this reaction is balanced, the water liberated must be removed and this operation cannot generally be carried out to completion in solution. Another disadvantage is associated with the etherification reaction discussed above; this reaction is conducted in the presence of a strong base, such as sodium methylate, and such a condition is not favorable to the stability of the imide rings introduced by the oligomers which are already formed, which can be at least partially open and, consequently, can result in degradation of the desired polyamidoimides.